RDF Schema (RDF-S) Language
An RDF Schema (RDF-S) Language is a vocabulary description language defined using the RDF language (to produce RDF vocabularies).
- Context:
- It can introduce Class Concepts.
- It can be a part of the RDF Standard.
- It can be used to create RDF Graphs.
- ...
- Example(s):
- OIL RDF Schema.
- ...
- See: OWL Ontology.
References
2023
- (Wikipedia, 2023) ⇒ https://en.wikipedia.org/wiki/RDF_Schema Retrieved:2023-6-8.
- RDF Schema (Resource Description Framework Schema, variously abbreviated as RDFS, , RDF-S, or RDF/S) is a set of classes with certain properties using the RDF extensible knowledge representation data model, providing basic elements for the description of ontologies. It uses various forms of RDF vocabularies, intended to structure RDF resources. RDF and RDFS can be saved in a triplestore, then one can extract some knowledge from them using a query language, like SPARQL.
The first version[1] was published by the World-Wide Web Consortium (W3C) in April 1998, and the final W3C recommendation was released in February 2014.[2] Many RDFS components are included in the more expressive Web Ontology Language (OWL).
- RDF Schema (Resource Description Framework Schema, variously abbreviated as RDFS, , RDF-S, or RDF/S) is a set of classes with certain properties using the RDF extensible knowledge representation data model, providing basic elements for the description of ontologies. It uses various forms of RDF vocabularies, intended to structure RDF resources. RDF and RDFS can be saved in a triplestore, then one can extract some knowledge from them using a query language, like SPARQL.
2013
- http://en.wikipedia.org/wiki/RDFS
- RDF Schema (Resource Description Framework Schema, variously abbreviated as RDFS, RDF(S), RDF-S, or RDF/S) is a set of classes with certain properties using the RDF extensible knowledge representation language, providing basic elements for the description of ontologies, otherwise called RDF vocabularies, intended to structure RDF resources. ...
2009a
- http://www.w3.org/TR/rdf-schema/
- This specification describes how to use RDF to describe RDF vocabularies. This specification defines a vocabulary for this purpose and defines other built-in RDF vocabulary initially specified in the RDF Model and Syntax Specification.
This specification introduces RDF's vocabulary description language, RDF Schema. It is complemented by several companion documents which describe RDF's XML encoding [ RDF-SYNTAX ], mathematical foundations [ RDF-SEMANTICS ] and Resource Description Framework (RDF): Concepts and Abstract Syntax [RDF-CONCEPTS]. The RDF Primer [RDF-PRIMER] provides an informal introduction and examples of the use of the concepts specified in this document.
- This specification describes how to use RDF to describe RDF vocabularies. This specification defines a vocabulary for this purpose and defines other built-in RDF vocabulary initially specified in the RDF Model and Syntax Specification.
2009b
- http://www.w3.org/TR/2004/REC-rdf-primer-20040210/#rdfschema
- RDF provides a way to express simple statements about resources, using named properties and values. However, RDF user communities also need the ability to define the vocabularies (terms) they intend to use in those statements, specifically, to indicate that they are describing specific kinds or classes of resources, and will use specific properties in describing those resources. For example, the company example.com from the examples in Section 3.2 would want to describe classes such as exterms:Tent, and use properties such as exterms:model, exterms:weightInKg, and exterms:packedSize to describe them (QNames with various "example" namespace prefixes are used as the names of classes and properties here as a reminder that in RDF these names are actually URI references, as discussed in Section 2.1). Similarly, people interested in describing bibliographic resources would want to describe classes such as ex2:Book or ex2:MagazineArticle, and use properties such as ex2:author, ex2:title, and ex2:subject to describe them. Other applications might need to describe classes such as ex3:Person and ex3:Company, and properties such as ex3:age, ex3:jobTitle, ex3:stockSymbol, and ex3:numberOfEmployees. RDF itself provides no means for defining such application-specific classes and properties. Instead, such classes and properties are described as an RDF vocabulary, using extensions to RDF provided by the RDF Vocabulary Description Language 1.0: RDF Schema [RDF-VOCABULARY], referred to here as RDF Schema.
RDF Schema does not provide a vocabulary of application-specific classes like exterms:Tent, ex2:Book, or ex3:Person, and properties like exterms:weightInKg, ex2:author or ex3:JobTitle. Instead, it provides the facilities needed to describe such classes and properties, and to indicate which classes and properties are expected to be used together (for example, to say that the property ex3:jobTitle will be used in describing a ex3:Person). In other words, RDF Schema provides a type system for RDF. The RDF Schema type system is similar in some respects to the type systems of object-oriented programming languages such as Java. For example, RDF Schema allows resources to be defined as instances of one or more classes. In addition, it allows classes to be organized in a hierarchical fashion; for example a class ex:Dog might be defined as a subclass of ex:Mammal which is a subclass of ex:Animal, meaning that any resource which is in class ex:Dog is also implicitly in class ex:Animal as well. However, RDF classes and properties are in some respects very different from programming language types. RDF class and property descriptions do not create a straightjacket into which information must be forced, but instead provide additional information about the RDF resources they describe. This information can be used in a variety of ways, which will be discussed in Section 5.3.
The RDF Schema facilities are themselves provided in the form of an RDF vocabulary; that is, as a specialized set of predefined RDF resources with their own special meanings. The resources in the RDF Schema vocabulary have URIrefs with the prefix http://www.w3.org/2000/01/rdf-schema# (conventionally associated with the QName prefix rdfs:). Vocabulary descriptions (schemas) written in the RDF Schema language are legal RDF graph s. Hence, RDF software that is not written to also process the additional RDF Schema vocabulary can still interpret a schema as a legal RDF graph consisting of various resources and properties, but will not "understand" the additional built-in meanings of the RDF Schema terms. To understand these additional meanings, RDF software must be written to process an extended language that includes not only the rdf: vocabulary, but also the rdfs: vocabulary, together with their built-in meanings. This point will be illustrated in the next section.
- RDF provides a way to express simple statements about resources, using named properties and values. However, RDF user communities also need the ability to define the vocabularies (terms) they intend to use in those statements, specifically, to indicate that they are describing specific kinds or classes of resources, and will use specific properties in describing those resources. For example, the company example.com from the examples in Section 3.2 would want to describe classes such as exterms:Tent, and use properties such as exterms:model, exterms:weightInKg, and exterms:packedSize to describe them (QNames with various "example" namespace prefixes are used as the names of classes and properties here as a reminder that in RDF these names are actually URI references, as discussed in Section 2.1). Similarly, people interested in describing bibliographic resources would want to describe classes such as ex2:Book or ex2:MagazineArticle, and use properties such as ex2:author, ex2:title, and ex2:subject to describe them. Other applications might need to describe classes such as ex3:Person and ex3:Company, and properties such as ex3:age, ex3:jobTitle, ex3:stockSymbol, and ex3:numberOfEmployees. RDF itself provides no means for defining such application-specific classes and properties. Instead, such classes and properties are described as an RDF vocabulary, using extensions to RDF provided by the RDF Vocabulary Description Language 1.0: RDF Schema [RDF-VOCABULARY], referred to here as RDF Schema.
2009c
- http://www.schemaweb.info/default.aspx
- SchemaWeb is a directory of RDF schemas expressed in the RDFS, OWL and DAML+OIL schema languages.
SchemaWeb is a place for developers and designers working with RDF. It provides a comprehensive directory of RDF schemas to be browsed and searched by human agents and also an extensive set of web services to be used by software agents that wish to obtain real-time schema information whilst processing RDF data.
RDF Schemas are the critical layer of the Semantic Web. They provide the semantic linkage that 'intelligent' software needs to extract value giving information from the raw data defined by RDF triples.
- SchemaWeb is a directory of RDF schemas expressed in the RDFS, OWL and DAML+OIL schema languages.
2007
- (Obitko, 2007) ⇒ Marek Obitko. (2007). “Translations Between Ontologies in Multi-agent Systems - Ontology Operations].” PhD Thesis, Czech Technical University http://www.obitko.com/tutorials/ontologies-semantic-web/rdf-schema-rdfs.html
- RDF Schema (RDFS) is extending RDF vocabulary to allow describing taxonomies of classes and properties. It also extends definitions for some of the elements of RDF, for example it sets the domain and range of properties and relates the RDF classes and properties into taxonomies using the RDFS vocabulary(...) All resources can be divided into groups called classes. Classes are also resources, so they are identified by URIs and can be described using properties. The members of a class are instances of classes, which is stated using the rdf:type property. Note that class and a set of instances does not have to be the same. The set of instances is the extension of the class, and two different classes may contain the same set of instances. For example, looking at the RDF example graph, class of people having mailbox mailto:joe.smith@example.org is different from the class of people having homepage http://www.example.org/~joe/, but the extension (i.e., the set of instances) of these classes is the same - it is the resource http://www.example.org/~joe/contact.rdf#joesmith.
In RDFS a class may be an instance of a class. All resources are instances of the class rdfs:Resource. All classes are instances of rdfs:Class and subclasses of rdfs:Resource. All literals are instances of rdfs:Literal. All properties are instances of rdf:Property (...)
Properties in RDFS are relations between subjects and objects in RDF triples, i.e., predicates. The properties as defined by RDFS are listed in the table with RDFS properties. All properties may have defined domain and range. Domain of a property states that any resource that has given property is an instance of the class. Range of a property states that the values of a property are instances of the class. If multiple classes are defined as the domain and range then the intersection of these classes is used (...)
- RDF Schema (RDFS) is extending RDF vocabulary to allow describing taxonomies of classes and properties. It also extends definitions for some of the elements of RDF, for example it sets the domain and range of properties and relates the RDF classes and properties into taxonomies using the RDFS vocabulary(...) All resources can be divided into groups called classes. Classes are also resources, so they are identified by URIs and can be described using properties. The members of a class are instances of classes, which is stated using the rdf:type property. Note that class and a set of instances does not have to be the same. The set of instances is the extension of the class, and two different classes may contain the same set of instances. For example, looking at the RDF example graph, class of people having mailbox mailto:joe.smith@example.org is different from the class of people having homepage http://www.example.org/~joe/, but the extension (i.e., the set of instances) of these classes is the same - it is the resource http://www.example.org/~joe/contact.rdf#joesmith.